SPWV-H: A Spatially-enhanced Vertical Adjustment Model for Global Precipitable Water Vapor

SPWV-H is a MATLAB-based computational model designed for estimating global precipitable water vapor (PWV) based on a spatially-enhanced vertical adjustment approach. The model interpolates PWV values from surface grid data, accounting for height-dependent variations and geographic location. By integrating both exponential interpolation and cubic polynomial adjustments, this model allows for accurate estimations of PWV across different altitudes and latitudes.Key Features:Grid-based Interpolation: The model uses surface grid data from three distinct datasets (SPWV-H1, SPWV-H2, SPWV-H3) to estimate PWV values.Vertical Adjustment: Implements an exponential model for height-based interpolation and applies a cubic polynomial correction for low-latitude regions where no land is present.Fourier-based Time Variability: The model incorporates Fourier terms based on the day of year (DOY) to account for annual and semi-annual PWV cycles, making it suitable for time-series analysis.Geographic Flexibility: PWV estimates are adjusted for different geographic regions, with special consideration for low-latitude zones (between -30° and 30° latitude).Applications:Climate Studies: Useful for analyzing water vapor variations over time and space, especially in the context of climate change and atmospheric water cycle studies.Weather and Climate Modeling: Enhances numerical weather prediction models by providing accurate vertical PWV profiles.Hydrological Studies: Can be used to estimate water vapor contributions to precipitation and soil moisture in regional hydrological models.Requirements:MATLAB (Version R2016b or later).Data files for the three SPWV grid datasets (SPWV-H1.txt, SPWV-H2.txt, SPWV-H3.txt).How to Use:Load Grid Data: The model requires pre-processed grid data that contains surface-level PWV values and geographic coordinates (latitude, longitude, height).Set Initial Parameters: Define input parameters such as the beginning and ending height (in km), the initial PWV value (in mm), latitude, longitude, and day of the year (DOY).Run the Model: Call the PWV_Interpolation_Model.m script, which applies the vertical adjustment and spatial interpolation to compute the PWV for specified regions and heights.Citation:Yang, H., Ferreira, V., He, X., Zhan, W., Wang, X., Ji, S., 2025. Spatially enhanced interpolating vertical adjustment model for precipitable water vapor. J. Geod. 99, 12. https://doi.org/10.1007/s00190-025-01936-8